This invention relates to inorganic, organometallic and organic compositions containing olefins and olefin epoxides rich in methyl side groups, and which exhibit hydrophobic and abhesive properties. These compositions are very economical for use in building materials, coating and impregnation materials, film and foil materials, etc. Preferred are the beta olefins and oxides thereof. The olefins and oxides are rich in methyl side groups and are also useful as reactive diluents, as plasticizers, and for the creation of an oxygen-poor reaction environment.
To impart hydrophobic and/or abhesive properties to materials, surfaces, etc. is of great technical and economical importance. Hydrophobicity protects surfaces from water, and consequently from corrosion. In some applications it is desirable to obtain sufficient hydrophobicity coupled with sufficient porosity to permit "breathing" of the treated materials and substrates. The abhesive properties are required if surface characteristics are desired in which adhesive materials will not adhere too strongly and from which they can easily be removed again without a residue on the abhesive surface. Such abhesive systems have gained considerable importance as release coatings on backings for pressure sensitive adhesive films and foils.
Many compounds to produce hydrophobic and abhesive materials have been described in the literature; they fulfill these functions to a greater or lesser degree, and their effectiveness and efficiency often depend on the material characteristics. According to today's state of the art a number of compounds are used to impart hydrophobicity and sometimes also abhesive properties, such as fatty substances, e.g. paraffins, waxes, metallic soaps; aluminium compounds, e.g. aluminium sulfate, acetate, and formiate; high molecular weight alkyl pyridinium compounds, alkyl isocyanates, substituted ethylene ureas, complex chromium compounds, silicones. To apply these compounds to be treated, they generally have to be dissolved in inert solvents first. These solvents have to be removed by evaporation after application which causes environmental problems or requires expensive recovery equipment. To impart abhesiveness the fatty substances, such as paraffins, waxes and metal soaps, have been generally replaced to day by the very expensive silicone materials since the abhesive properties of the former compounds no longer satisfy the high technical requirements.
The newer hydrophobic and/or abhesive materials based on polyorganosiloxanes have a number of good properties, however, they do not satisfy all requirements. These problems can be related to the following facts. They often have to be applied as solutions in organic solvents. They often require high hardening and polymerization temperatures. Solvent-based systems release the solvent during hardening and drying. These solvent vapors are either released into the atmosphere or they have to be collected in rather expensive recovery equipment. These silicones are several times more expensive than the more conventional products; thus, they often cannot be applied in sufficient amounts to obtain the required hydrophobicity or abhesiveness of the treated substrate for economical reasons.
Thermo-sensitive materials and substrates cannot be treated with the hydrophobicity- and/or abhesiveness-imparting products which have to be hardened and polymerized at higher temperatures. The exposure to heat changes the original shape of the substrate and often even its structure. Materials and substrates which contain some moisture can withstand brief exposure to heat, such as cellulosic materials and paper sheets; however they generally have to be remoistened by exposure to water vapor to regain their original properties, such as planeness and flexibility. This remoistening procedure is not only expensive and energy intensive, its effectiveness is also in doubt by many skilled in this art.
The functionality which causes hydrophobicity and abhesiveness in organosiloxanes is well understood and described in the literature. These properties are not only determined by the nonpolarity of the side chains of the molecule, but are greatly affected by as high a content of nonpolar methyl side groups per molecule unit as possible The content of unpolar methyl side groups actually determines the hydrophobicity and abhesiveness. The functionality which causes hydrophobicity and abhesiveness can easily be shown on the so-called "brush-effect" of a dimethyl polysiloxane compound: ##STR2##
This schematic shows also that because of the basic structure of polydimethylsiloxanes the content of the important methyl side groups is limited to 2 per Si-O unit.
Many attempts have been made to decrease the cost of imparting hydrophobicity and abhesiveness to materials and substrates. This task was generally unsuccessful since it was difficult to increase the content of methyl side groups in existing compounds, and since other compounds richer in methyl side groups were not economically available.
Controlled release, i.e., adjusting the release force over a wide range as desired for different requirements, for release coated paper and foil backings for pressure sensitive release systems has long been a goal of the industry. Obtaining this goal has been frustrated to far by the inability to economically increase the nonpolar methyl side group content in these compounds, and since it was not possible to achieve a statistically uniform distribution of the methyl groups along the backbone of the molecule.
In free-radical polymerization, hardening and crosslinking of unsaturated compounds, such as polyester resins, acrylic and methacrylic resins, the oxygen in the air inhibits curing of the surface. The oxygen destroys the free radicals; thus, the hardening reaction is inhibited and the surface remains sticky. Attempts were made to protect the surface from the oxygen in the air by covering it with foils, glass plates, etc. However, this was technically impractical. It was then suggested to add paraffin to these systems (Ger. Pat. No. PS 948 818). The paraffin floats to the surface during hardening and forms a protective coating against the oxygen. However, this paraffin addition created several problems. The most important problems encountered are: paraffin crystallizes at lower temperatures from the hardenable materials; at higher temperatures it no longer floats to the surface. It is also well known that paraffin-containing systems will not harden at high temperatures. Thus, with paraffin-containing systems it is not possible to obtain short reaction times using high temperatures since the system can only be heated until the paraffin has floated out completely. The industry has been waiting for improved solutions for a long time because the paraffin-containing hardenable compounds are excellent polishable compounds.